Updating shower trim

Good day all. I'm a new subscriber and need a little assistance. I'm in process of updating shower with new door, shower head and handles. Question relates to value, stem & handles. Is the value universal, i.e. can I install Moem stems in a Delta value or am I restricted to the original make and how do I identify the manufacture. Any suggestions as to my options would be greatly appreciated.

Virtually NO interchangeability between brands, and even between different models of the same brand.

Your choices will be limited depending on how common your model is. You may be able to find the same trim in an updated color like brush nickel, and you might even be able to find a different style. Pictures please.

Last summer I wanted to update the trim on my Delta shower/tub valve. Found that while the cartridges are still available, the trim isn't. This lead to the new Delta 1700 control which I love, and it meets current code requirements.